Zanclus cornutus - The Moorish Idol is not an Angelfish, nor a Butterflyfish, but rather a close relative of the Acanthruidae or Surgeonfish family. It is the one and only member of the Zanclidae family. They are found from Hawaii to Australia, and from the west coast of Central America westward to the coast of Africa and the Red Sea.
They should be provided with plenty of unobstructed swimming space, as well as ample hiding places to take refuge when feeling threatened. A minimum tank size of 100 gallons is recommended.
Moorish idols suffer from the reputation of being hard to care for. This is not necessarily true. The greatest difficulty in keeping them is getting them to eat. WE DO NOT SELL MOORISH IDOLS THAT ARE NOT EATING IN OUR TANKS. PERIOD!
The other area to be careful of is the other fish you have in your tank. Moorish idols should not be kept with triggerfish, or other aggressive fish that might nip at it's delicate dorsal fin.